Question

if 8,x,2x and 9 are in proportion. find the positive value of x

Answer 1

$\displaystyle\huge\red{\underline{\underline{Solution}}}$

FORMULA TO BE IMPLEMENTED

Four given numbers a, b, c, d are said to be in proportion if

$a : b \: = c \:: d$

TO DETERMINE

Find the positive value of x If 8,x,2x and 9 are in proportion

CALCULATION

Since 8,x,2x and 9 are in proportion

So

$8 \:: \: x = 2x \:: 9$

$\implies \: \displaystyle \: \frac{8}{x} = \frac{2x}{9}$

$\implies \: \displaystyle \: 2 {x}^{2} = 72$

$\implies \: \displaystyle \: {x}^{2} = 36$

$\implies \: \displaystyle \: x = \pm \: 6$

Since x is positive

So x = 6